This invention relates to a tone generation device for an electronic musical instrument and, more particularly, to a tone generation device for an electronic musical instrument capable of producing multiple tone source effects such as a stereophonic effect and a reverberation effect.
For producing a stereophonic effect in an electronic musical instrument, it is necessary to prepare tone sources respectively for left and right channels. According to a prior art system, for example, a stereophonic system is composed, as shown in FIG. 3, by providing a left channel tone source section and a right channel tone source section independently from each other and connecting sound systems respectively to these tone sources.
In the prior art system shown in FIG. 3, two tone sources which produce tones corresponding to strong and weak key touches are provided in each of the left and right channel tone source sections, and outputs of these two tone sources are added together by addition means to form a left channel tone source and a right channel tone source. Thirty-two tones are used for each tone source, so that, in the case of an electronic musical instrument employing a waveform memory storing tone waveforms of a tone source, it is necessary to store waveform data of 32.times.2=64 as waveforms corresponding to the strong touch tones and weak touch tones of the thirty-two tones and, since these waveforms must be prepared for both the left and right channels, it is ultimately necessary for the waveform memory to store 64.times.2=128 waveform data.
In addition to this problem of generating and storing a large number of waveforms, there arises difficulty in matching phases of the left and right channel tone waveforms with a resulting discrepancy in the produced tone image.
It is, therefore, an object of the invention to provide a tone generation device for an electronic musical instrument capable of producing multiple tone source effects such as a stereophonic effect and reverberation effect without generating and storing a large number of waveforms.